LOCALIZED STAGES IN DEVELOPMENT. 145 



Aquilegia canadensis. 



Fig. 16. Seedling showing cotyledons and trifoliolate first nepionic leaf. XU- P. 93. 



Fig. 17. Leaf of adult, the distal end with its major indentations is comparable to the whole nepionic leaf. Xj. Figs. 

 16-17 cultivated, Dorchester, Mass. P. 93. 



Rhus toxicodendron. 



Fig. 18. Seedling showing cotyledons and nepionic leave.«, the first two opposite, succeeding leaves alternate, all tri- 

 foliolate with lobes in the proximal leaflets. West Chop, Martha's Vineyard, Ma.ss. XI- P. 97. 



AmPELOPSIS QriNQUEFOLIA. 



Fig. 19. Seedling .showing ovate cotyledons and three nepionic leaves, all alternate, 1,2, trifoliolate, but leaf 3 is ijuiniiiie- 

 foliolate, like the adult. West Chop, Martha's Vineyard, Mass. Xh- P. 97. 

 Figs. 16-17 drawn by_Mr. J. H. Emerton ; others by the author. 



PLATE 17. 



Ampelopsis triccspidata. 



Fig. 20. Seedling showing broadly ovate cotyledons and alternate, trifoliolate, nepionic leaves. Xl. P. 98. 



Fig. 21. Tip of an older seedling. Leaf 1 is trifoliolate, as are all the leaves proximally in this specimen. Leaf 2 has 

 a lateral leaflet on one side. Later leaves are all unifoliolate, dentate. Xj- Figs. 20-21, Shady Hill nursery. P. 98. 



Fig. 22. Typical unifoliolate, trilobed leaf from old wood of adult. Compare Fig. 25b. XL P. 98. 



Fig. 23. Trifoliolate leaf from base or nepionic area of adult vine. Compare Figs. 20 and 25a. Xl- P. 98. 



Fig. 24. Unifoliolate, dentate leaves from wood of current season's growth. Compare Figs. 21 and 25c. Xi- Figs. 

 22-24 ail from one vine, cultivated. Vineyard Haven, Mass. P. 98. 



Fig. 25. Diagi-am showing distribution of types of leaves in adult vine raised from seed. Area a, near base of vine, 

 leaves trifoliolate ; area b, old wood, leaves unifoliolate, trilobed ; area c, wood of current season's growth, leaves unifoliolate, 

 cordate, dentate. Compare with Figs. 20-24. P. 98. 



Acer rubrum. 



Fig. 26. Tip of branch of adult, with young leaves, all elongate, trilobed, e.speeially leaf 2. X\- P. 99. 



Fig. 27. Sucker from base of adult tree. Leaves, especially 2, elongate, trilobed. XJ. Figs. 26-27. West Chop, 

 Martha's Vineyard, Mass. P. 99. 



Fig. 28. Seedling, cotyledons elongate, nepionic leaves, 1 neai'ly ovate, dentate, 2 elongate, trilobed. Jackson, N. H. 

 Xl. P. 99. 



Fig. 29. End of branch of adult showing, 1 typical leaf of species, and 3 a, b elongate trilobed leaves. West Chop, 

 Martha's Vineyard, Mass. Xh P- 99. 



Acer oblonc.um. 



Fig. 30. Species having elongate, entii-e leaves, the veining is similar to that of the Red Maple, Fig. 29. Xj- Province 

 of Hupeh, China. X^. P. 100. 



Acer carpinifolium. 

 Fig. 31. Species having leaves with slightly .serrate margin, but no lobes. Nikko, Japan. X J. P- 100. 



Acer crataegifolium. 

 Fig. 32. Species having leaves with slightly developed lobes, compare the two leaves of this figure, with leaves 1, 1, f 

 Fig. 28. Nikko, Japan. X |. P. 100. 



